WO2007138869A1 - Codeur - Google Patents

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Publication number
WO2007138869A1
WO2007138869A1 PCT/JP2007/060117 JP2007060117W WO2007138869A1 WO 2007138869 A1 WO2007138869 A1 WO 2007138869A1 JP 2007060117 W JP2007060117 W JP 2007060117W WO 2007138869 A1 WO2007138869 A1 WO 2007138869A1
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WO
WIPO (PCT)
Prior art keywords
track
encoder
light
pattern
signal
Prior art date
Application number
PCT/JP2007/060117
Other languages
English (en)
Japanese (ja)
Inventor
Akihiro Watanabe
Toru Imai
Original Assignee
Nikon Corporation
Sendai Nikon Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nikon Corporation, Sendai Nikon Corporation filed Critical Nikon Corporation
Publication of WO2007138869A1 publication Critical patent/WO2007138869A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
    • G01D5/34776—Absolute encoders with analogue or digital scales
    • G01D5/34792—Absolute encoders with analogue or digital scales with only digital scales or both digital and incremental scales
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/36—Forming the light into pulses
    • G01D5/38—Forming the light into pulses by diffraction gratings

Definitions

  • the present invention relates to an encoder, and more particularly to an encoder that can optically detect absolute position information of a moving body.
  • an encoder capable of detecting absolute position information of a moving body without performing an origin return operation has been used.
  • Such an encoder is generally called an absolute encoder (absolute encoder).
  • absolute encoder absolute encoder
  • the detection unit pattern corresponding to one detection unit must be different from the detection unit patterns at other positions.
  • a scale is provided with a plurality of parallel tracks corresponding to each bit (for example, in the case of 16 bits, 16 parallel tracks corresponding to each bit are provided).
  • this type requires at least N tracks to achieve 2 N resolution, so the higher the resolution, the larger the scale and the higher the cost.
  • a serial bit string pattern for example, a single-line pattern representing an M-sequence (Maximum length code) formed on a single track has been used (for example, patent literature). 1).
  • Patent Document 1 Japanese Patent No. 2699542
  • the present invention has been made under the above circumstances, and from a first viewpoint, a pattern having a first track in which a pattern associated with absolute position information is formed along a predetermined direction.
  • a kale substrate a beam irradiation device that moves relative to the scale substrate in the predetermined direction and irradiates a part of the first track with illumination light; and the beam irradiator that irradiates a part of the first track;
  • An encoder that periodically varies the irradiation position of the illumination light in the predetermined direction.
  • FIG. 1 is a diagram showing a schematic configuration of an encoder according to an embodiment of the present invention.
  • FIG. 2 is a top view of the moving scale.
  • FIG. 3 is an optical path diagram of the encoder of FIG.
  • FIGS. 4 (A) to 4 (E) are diagrams showing variations in the incident position of diffracted light on a track.
  • FIG. 5 is a diagram showing a schematic configuration of a detection device 80.
  • FIG. 6 is a diagram showing 9-bit serial data output from a circuit 70.
  • FIG. 7 is an optical path diagram of light irradiated on a track 33.
  • FIG. 8 (A) is a diagram showing the top surface force of each bit region
  • FIG. 8 (B) is a diagram showing an example of detection of reflected light.
  • FIG. 1 shows a schematic configuration of a main part of an encoder 10 according to an embodiment of the present invention.
  • the encoder 10 includes a light source 12, a vibrating mirror 14, a drive device 16, a collimator lens 18, a beam generation unit 20, a beam splitter 22, an objective lens 23, a moving scale 24, and light receiving elements 26 to 26, 27.
  • the moving scale 24 constituting the encoder 10 is attached to a moving body (not shown), and moves in the X-axis direction as the moving body moves.
  • the moving scale 24 is a reflection type scale made of glass, for example, and a reflection layer having a force such as chromium (Cr) is formed thereon.
  • the tracks 31, 32 are provided with elongated patterns extending in the X-axis direction. Tracks 31 and 32 are delimited at a constant pitch in the X-axis direction, and a pattern indicating a value of "0" or "1" is formed in each area (bit area) delimited by the pitch. Has been.
  • the pattern of tracks 31 and 32 is a serial bit string pattern extending in the X-axis direction. Such a pattern can be realized, for example, by making the reflectance different between the “0” pattern and the “1” pattern. In FIG. 2, the pattern showing the value “0” is shown in white, and the pattern showing the value “1” is shown in black.
  • the pattern is formed with 9 bits as the detection unit for the number of bits detected simultaneously.
  • the bit string In the bit strings of tracks 31 and 32, regardless of where 9 consecutive bits are extracted, the bit string has a unique value at that position. Therefore, in the tracks 31 and 32, it is possible to recognize the position of the bit string pattern corresponding to which position of the moving scale 24 is read by reading the 9-bit value among the continuous bit strings.
  • an M-sequence bit string pattern can be employed.
  • bits corresponding to the same X position of tracks 31 and 32 are inverted. That is, if the value of the bit of track 31 at a certain X position is “0”, the value of the bit of track 32 at that X position is “1”, and the bit of track 31 at the other X position. If the value of “1” is “1”, the value of the bit of the track 32 at the X position becomes “0”!
  • the track 33 is provided with a periodic pattern whose periodic direction is the X-axis direction.
  • This periodic pattern is, for example, a sinusoidal phase grating, and the grating pitch is, for example, This is set to be the same as the pitch of tracks 31 and 32.
  • FIG. 3 shows an optical path diagram of light irradiated on the track 31.
  • the vibrating mirror 14 reflects the laser light from the light source 12 toward the collimator lens 18.
  • the oscillating mirror 14 is periodically oscillated in the rotational direction around the Y axis by a driving device 16 (see FIG. 1) having an actuator such as a piezo element or a crystal resonator. Due to this rotational vibration, the reflection direction of the laser light incident on the oscillating mirror 14 varies according to the direction of the varying reflecting surface, and this variation causes the angle of the laser light incident on the collimator lens 18 to be periodically changed. Change.
  • the collimator lens 18 converts the laser light reflected by the vibrating mirror 14 into parallel light.
  • This parallel light is incident on the beam generator 20.
  • three diffraction gratings 41, 42, and 43 whose periodic direction is the X-axis direction are arranged at equal intervals in the Y-axis direction.
  • the diffraction grating 41 is provided closest to the + Y side, and the diffraction grating 43 is disposed so as to be sandwiched between the diffraction gratings 41 and 42.
  • the grating pitches of the diffraction gratings 41 and 42 are the same.
  • the grating pitch of the diffraction grating 43 may be the same as or different from the grating pitch of the diffraction gratings 41 and 42.
  • the diffraction gratings 41, 42 and 43 are transmissive phase gratings.
  • the parallel light transmitted through the diffraction gratings 41, 42, and 43 is diffracted to generate a plurality of diffracted lights.
  • the 0th order light and the ⁇ 1st order diffracted light (in Fig. 3, the diffracted light emitted to the + X side is defined as the + 1st order diffracted light and emitted to the X side The first order diffracted light).
  • the zero-order light and the first-order diffracted light are incident on the beam splitter 22, and part of them are transmitted.
  • Each diffracted light transmitted through the beam splitter 22 enters the objective lens 23, is converted into light parallel to the Z axis, and then enters the moving scale 24.
  • FIGS. 4A to 4E show the movement of the incident positions of the three diffracted lights incident on the track 31.
  • the incident position of the next light is indicated by a black circle, and the incident position of the + first-order diffracted light is indicated by an X surrounded by a circle.
  • the interval between the incident positions of the 1st-order diffracted light, 0th-order light, and + 1st-order diffracted light is set to be 3 times (3p) the pitch of the bit pattern of the track 31. Is set.
  • the incident positions of the 0th-order light and the ⁇ 1st-order diffracted light vibrate in the X-axis direction while maintaining the mutual distance.
  • the amplitude (half amplitude) of this vibration is set to be the same as the pitch p of the bit pattern. Therefore, the incident positions of the three diffracted lights at the position shown in FIG. 4 (A) sequentially move to the positions shown in FIGS. 4 (B) to 4 (E). That is, the incident positions of the 0th-order light and the ⁇ 1st-order diffracted light reciprocate in an area corresponding to 3 bits, respectively, at regular intervals. As a result, the incident positions of the three diffracted lights move with a width equivalent to 9 bits as a whole.
  • Each diffracted light reflected by the track 31 of the moving scale 24 is bent by the beam splitter 22 through the objective lens 23 and proceeds in the ⁇ X direction.
  • the first-order diffracted light reaches the light-receiving element 27, the zero-order light reaches the light-receiving element 27, and the + first-order diffracted light is received.
  • a photoelectric conversion signal is output.
  • Each of these photoelectric conversion signals includes information on the value of the bit in the track 31 on which the 1st-order diffracted light, the 0th-order light, and the + 1st-order diffracted light are incident.
  • the optical path of the light incident on the track 32 is almost the same as that shown in FIG. 3, and the first-order diffracted light, the 0th-order light, and the + first-order diffracted light incident on the track 32 are received by the light receiving elements 28, 28, Receive light at 28
  • a detection device 80 shown in FIG. 5 includes differential amplifier circuits 51, 52, 53, demultiplexers 55, 56, 57, a latch circuit 60, and a parallel-serial conversion circuit 70.
  • the signal (current signal) is converted into a voltage signal by a current-voltage conversion circuit (not shown).
  • the photoelectric from the light receiving element 27 is Difference value between conversion signal (voltage signal) and photoelectric conversion signal (voltage signal) from light receiving element 28
  • the electric conversion signal (current signal) is converted into a voltage signal by a current / voltage conversion circuit (not shown) and then input to the differential amplifier circuit 52.
  • the differential amplifier circuit 52 the light receiving element 27
  • the difference value is amplified and output.
  • the photoelectric conversion signal from the light receiving element 27 current signal
  • the photoelectric conversion signal (current signal) 3 is converted into a voltage signal by a current-voltage conversion circuit (not shown) and then input to the differential amplifier circuit 53.
  • the photoelectric conversion signal (voltage signal) from the light receiving element 27 and the light from the light receiving element 28 are converted into a voltage signal by a current-voltage conversion circuit (not shown) and then input to the differential amplifier circuit 53.
  • the photoelectric conversion signal (voltage signal) from the light receiving element 27 and the light from the light receiving element 28 are
  • the demultiplexer 55 switches the output destination of the signal input from the differential amplifier circuit 51 at a predetermined interval. This switching timing is synchronized with the drive signal of the vibration mirror 14 issued from the drive device 16.
  • the drive signal of the vibrating mirror 14 is a sine wave signal, and the output destination of the signal is switched every time the phase of the sine wave changes by 60 degrees. In this way, in the latch circuit 60, values corresponding to the values indicated by the bit patterns of the track 31 irradiated with the first-order diffracted light are respectively latched.
  • the demultiplexers 56 and 57 are also synchronized with the drive signal of the drive mirror 14, and the latch circuit 60 receives the values of the bits of the tracks 31 and 32 irradiated with the 0th-order light and the + first-order diffracted light. Each will be latched.
  • the latch timing is set to be the same as the cycle of the vibrating mirror 14.
  • a signal corresponding to the value of each bit latched by the latch circuit 60 is input to the parallel-serial conversion circuit 70.
  • the normal-to-serial conversion circuit 70 generates 9 bits of parallel data input from each bit of the latch circuit 60 and 9 bits read from the track 31. Converts to 9-bit serial data according to the column pattern, and outputs the serial data as absolute position information of moving scale 24. For example, if the 9-bit pattern 1S of track 31 is as shown in Fig. 6 (A), the 9-bit serial data output from the parallel-serial conversion circuit 70 is as shown in Fig. 6 (B). .
  • FIG. 7 shows an optical path diagram of light irradiated on the track 33.
  • the laser light emitted from the light source 12 is reflected by the vibrating mirror 14, converted into parallel light by the collimator lens 18, and enters the diffraction grating 43.
  • the first-order diffracted light, the 0th-order light, and the + first-order diffracted light emitted from the diffraction grating 43 are incident on the track 33 on the moving scale 24 through the beam splitter 22 and the objective lens 23.
  • the reflected light of the incident light on the track 33 is the periodic pattern of the incident position of the incident light.
  • the light contains information about the phase of the turn.
  • This reflected light passes through the objective lens 23 and is reflected by the beam splitter 22.
  • the reflected light of the first-order diffracted light enters the light-receiving element 26, the zero-order light enters the light-receiving element 26, and the reflected light of the + first-order diffracted light.
  • the incident positions of the first-order diffracted light, the zeroth-order light, and the + first-order diffracted light on the track 33 also periodically vary in the X-axis direction. Due to this variation, the phase information of the incident position included in each reflected light in the periodic pattern of the track 33 is modulated.
  • Light receiving elements 26, 26, 26 forces The photoelectric conversion signals that are output are sent to the detection device 80.
  • the detection device 80 demodulates the phase information of the periodic pattern included in these photoelectric conversion signals, and outputs the demodulated phase information as position information of the moving scale 24.
  • the configuration and operation of the circuit inside the detection device 80 that demodulates the phase information and outputs the position information of the moving scale 24 see, for example, JP 2000-511634A or US Pat. No. 6,639. , No. 686.
  • national legislation in the designated country (or selected selected country) designated in this international application the disclosure in the above US patent specification is incorporated herein by reference.
  • the final absolute position of the moving scale 24 is based on the absolute position information obtained from the tracks 31 and 32 and the phase information of the periodic pattern obtained from the track 33. Generate information. As a result, the minimum reading unit of absolute position information obtained from tracks 31 and 32 is set to one cycle of the cycle pattern of track 33, and this cycle is further interpolated. Position information can be detected.
  • the encoder 10 is incorporated in a part of a device manufacturing processing apparatus for manufacturing a device such as a semiconductor device!
  • the device manufacturing processing apparatus is provided with a fixed part (not shown) whose position is fixed and a movable part (not shown) movable with respect to the fixed part.
  • the part (beam irradiation device) other than the moving scale 24 of the encoder 10 in FIG. 1 is attached to the fixed part, and the moving scale 24 is attached to the movable part. That is, the encoder 10 detects the relative displacement in the X-axis direction of the movable part with respect to the fixed part of the device manufacturing processing apparatus.
  • the encoder 10 After the device manufacturing processing apparatus is powered on, power supply to the encoder 10 is also started, and laser light emission from the light source 12 is started. At this stage, the encoder 10 first generates and outputs final absolute position information based on the absolute position information obtained from the tracks 31 and 32 and the phase information of the periodic pattern of the track 33. Therefore, in the device manufacturing processing apparatus, it is possible to acquire the absolute position information of the movable part with respect to the subsequent fixed part without performing the origin return operation of the movable part. Thereafter, the encoder 10 may detect the displacement of the movable portion based on the phase information of the periodic pattern obtained from the track 32.
  • the diffraction gratings 41 and 42 that diffract the laser light emitted from the light source 12 and generate a plurality of diffracted lights as a plurality of beams are provided. Then, the first-order diffracted light, the 0th-order light, and the + first-order diffracted light generated by the diffraction gratings 41 and 42 are irradiated onto a part of the tracks 31 and 32. In this way, since it is not necessary to provide a plurality of light sources to generate a plurality of beams, it is possible to further reduce the size and cost of the apparatus. wear.
  • the diffraction gratings 41 and 42 are used as optical elements that generate a plurality of beams, but other optical elements may be used. Examples include beam splitters (including polarizing beam splitters), half mirrors, birefringent prisms, and splitting prisms. Further, by arranging an acousto-optic element (AOM) or an electro-optic element (EOM) as the beam generator, the interval between the beams irradiated to the track may be adjustable.
  • AOM acousto-optic element
  • EOM electro-optic element
  • the irradiation positions of a plurality of beams are periodically changed in the X-axis direction. In this way, more information can be acquired with a smaller number of beams, so that the encoder can be increased in size and cost.
  • the incident position of each diffracted light is periodically changed in the X-axis direction by rotating the vibrating mirror 14 around the Y-axis, but the present invention is not limited to this.
  • a vibrating mirror instead of a vibrating mirror, a crystal, a tuning fork type crystal, or the like may be used. Such crystals have the advantage of low power consumption due to their low resonant frequency.
  • the drive device for driving the vibrating mirror may be replaced with a simple reflecting mirror so that the position of the light source 12 is periodically changed to the Z axis.
  • the position of the collimator lens 18 may be periodically changed in the X-axis direction without changing the position of the light source 12.
  • the pattern of the track 31 of the moving scale 24 is formed according to the code bit sequence (M sequence) associated with the absolute position information.
  • the moving scale 24 further includes a track 32 in which a pattern of one row representing a bit sequence in which the value of each bit of the M sequence is inverted is formed in the X-axis direction.
  • the difference between the signal corresponding to the light reception result via part of the track 31 pattern and the signal corresponding to the light reception result via part of the track 32 pattern is obtained. Based on this, the relative movement between the moving scale 24 and the beam irradiation device is detected.
  • the detection device 80 may detect the absolute position information based on the sum of the signal obtained from the track 31 and the signal obtained from the track 32 and based on the sum signal. .
  • the moving scale 24 further includes a track 33 having a periodic pattern that is sandwiched between the track 31 and the track 32 and formed along the X-axis direction.
  • the track 33 of the periodic pattern is configured to be sandwiched between the tracks 31 and 32 of the two absolute patterns, the tracks 31 and 32 are rotated by the rotation of the moving scale 24 around the Z axis (ie, skewing). The deviation between the absolute position information obtained and the relative position information obtained from the track 32 can be reduced.
  • the intensity of the reflected light (the intensity level of the reflected light) is varied depending on the value of the bit.
  • the present invention is not limited to this, and various patterns can be applied to the bit region.
  • an optical element having a different direction of reflected light emission may be provided.
  • mirrors with different inclination amounts of the reflecting surface may be formed in each bit area for the bit pattern “0” and the bit pattern “1”.
  • the laser beam may be transmitted through only one of the “0” and “1” patterns.
  • a diffraction grating can be employed as an optical element provided on the bit region.
  • a diffraction grating a blazed diffraction grating as shown in FIG. 8 (A) can be adopted.
  • a blazed diffraction grating is provided in each bit region of the track 31 ′.
  • the blazed diffraction grating is a diffraction grating in which the cross-sectional shape of the groove is a saw-tooth shape, and is a diffraction grating concentrated in a certain range of the spectral intensity of the diffracted light.
  • the periodic direction of the blazed diffraction grating is the Y-axis direction.
  • the blazed diffraction grating corresponding to a value of “0” is set so that the diffraction direction of the incident light is inclined to the + Y side.
  • the blazed diffraction grating corresponding to the value “” is set so that the diffraction direction of the incident light is inclined to the Y side.
  • FIG. 8 (B) there are two directions of travel of diffracted light by the blazed diffraction grating.
  • Light receiving elements 127 and 128 are provided. In this way, it is possible to separate a light receiving element that receives diffracted light including information “0” from a light receiving element that receives diffracted light including information “1”, so that the serial bit string pattern is more It becomes possible to read accurately.
  • the periodic direction of the blazed diffraction grating is not limited to the Y-axis direction as shown in FIG.
  • the periodic direction may be, for example, the X-axis direction, and when + Y is the 0 o'clock direction, the period direction of the blazed diffraction grating in the bit region of “0” is the 1:30 half direction.
  • the period direction of the blazed diffraction grating in the bit region of “1” may be set to 7:30.
  • the emission direction of the reflected light may be different between the bit area “0” and the bit area “1”.
  • the amplitude of the incident position of each diffracted light is set to a width corresponding to three times the pitch of the bit pattern of tracks 31 and 32, that is, a width corresponding to 3 bits, and the incident position of each diffracted light is
  • the interval is 3 bits, this is not restrictive.
  • the amplitude of the incident position of each diffracted light may be 2 bits or 4 bits or more, and the interval between the incident positions of each diffracted light may be 2 bits or 4 bits or more.
  • the amplitude and interval of the incident position of each diffracted light is determined by the number of bits to be read at a time.
  • the bit pattern read at a time using the continuous 9 bits on the tracks 31 and 32 as a reading unit may not be continuous.
  • the bit pattern interval is small, information of a plurality of bits separated according to the interval of the diffracted light may be read.
  • three diffracted lights of 1st order diffracted light, 0th order light, and + 1st order diffracted light are used as detection light.
  • higher order diffracted light may be used as detection light.
  • the diffraction gratings 41 and 42 are sine wave gratings, and only the first-order diffracted light and the + 1st-order diffracted light may be used as detection light. Furthermore, it is possible to have only one beam without providing the beam generator 20!
  • the force formed by the pattern formed on the tracks 31 and 32 as the pattern of the M-sequence serial bit string is not limited to this. Any pattern can be used as long as it is a bit string pattern (for example, a binary cyclic random number string).
  • the configuration of the absolute position information detection device 80 is not limited to that shown in FIG. 5, and the design can be changed as appropriate. In short, any circuit configuration that can accurately detect the absolute position information of the moving scale 24 from the bit string read by the fluctuation of the illumination light by the detection device 80 may be used.
  • the configuration of the optical system for detecting the phase information of the periodic pattern of the track 33 is not limited to the three-beam system as in the above-described embodiment, and any configuration can be used.
  • a configuration in which the diffraction grating 43 is not provided and parallel light incident on the track 33 is allowed to pass through and the objective lens 23 forms one beam spot on the periodic pattern of the track 33 may be used.
  • the + first-order diffracted light from the diffraction grating 43 and the first-order diffracted light interfere with each other to generate an interference fringe, and the interference fringe and the relative pattern of the track 33 relative to each other are generated.
  • the phase information of the periodic pattern of the track 33 may be detected on the basis of a typical positional deviation.
  • the moving scale 24 is attached to the moving body, and the moving displacement is detected.
  • the scale is fixed and the beam irradiation apparatus is attached to the moving body.
  • the displacement of the beam irradiation device relative to the scale may be detected.
  • the encoder 10 is a linear encoder, but the present invention can also be applied to a rotary encoder that detects the amount of rotation of the rotating body.
  • the absolute pattern similar to that on the tracks 31 and 32 and the periodic pattern of the track 33 are arranged concentrically on the scale substrate.
  • the position information of the moving scale 24 is detected based on the absolute position information of the M-sequence bit string pattern formed on the tracks 31 and 32 and the phase information of the periodic pattern of the track 33.
  • the tracks 31 and 32 may be provided, and the position information of the moving scale 24 may be detected from these M-sequence bit string patterns.
  • only track 31 is provided, and only from the M-sequence bit string pattern, The position information of the moving scale 24 may be detected.
  • the scale is not limited to a one-dimensional scale, and may be a two-dimensional scale.
  • the force encoder 10 described in the example in which the encoder 10 is attached to the device manufacturing processing apparatus can be attached to an NC machine tool or the like.
  • the wavelength of the laser beam and the value of the pitch in the track in the above embodiment are merely examples, and are appropriately determined according to the resolution required for the encoder. In general, the smaller the pattern pitch in a track, the better the encoder resolution.
  • the encoder of the present invention is suitable for accurately detecting the position information of the moving body.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Transform (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)

Abstract

Un intervalle de séparation de points d'incidence d'un faisceau lumineux de diffraction d'ordre -1, d'un faisceau lumineux de diffraction d'ordre 0 et d'un faisceau lumineux de diffraction d'ordre +1 est choisi de façon à correspondre à trois fois (3p) un pas de motif binaire d'une piste (31). Un dispositif d'entraînement anime un miroir vibrant (14) d'un mouvement vibratoire rotationnel pour faire vibrer les points d'incidence des faisceaux lumineux de diffraction d'ordre 0 et d'ordre ±1 dans la direction d'un axe X tout en maintenant leur intervalle de séparation. L'amplitude (la demi-amplitude) des vibrations est fixée à une valeur correspondant au pas (p) du motif binaire. Les points d'incidence des faisceaux lumineux d'ordre 0 et d'ordre ±1 se déplacent entre des régions équidistantes correspondant à trois bits. L'invention permet la lecture d'informations de position absolue sur 9 bits à l'aide de trois faisceaux lumineux de diffraction.
PCT/JP2007/060117 2006-05-25 2007-05-17 Codeur WO2007138869A1 (fr)

Applications Claiming Priority (2)

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JP2006-145920 2006-05-25
JP2006145920A JP2007315919A (ja) 2006-05-25 2006-05-25 エンコーダ

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8529823B2 (en) 2009-09-29 2013-09-10 Asml Netherlands B.V. Imprint lithography
JP2016053570A (ja) * 2014-09-03 2016-04-14 有限会社ファインチューン アブソリュート型エンコーダ
JP2017116306A (ja) * 2015-12-22 2017-06-29 株式会社ミツトヨ エンコーダ

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JP2016217782A (ja) * 2015-05-15 2016-12-22 日本電産サンキョー株式会社 位置検出装置
JP2016217783A (ja) * 2015-05-15 2016-12-22 日本電産サンキョー株式会社 位置検出装置

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JPH07134045A (ja) * 1993-11-11 1995-05-23 Nikon Corp アブソリュートエンコーダ
WO2006064801A1 (fr) * 2004-12-13 2006-06-22 Nikon Corporation Codeur photoélectrique

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WO2006064801A1 (fr) * 2004-12-13 2006-06-22 Nikon Corporation Codeur photoélectrique

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8529823B2 (en) 2009-09-29 2013-09-10 Asml Netherlands B.V. Imprint lithography
JP2016053570A (ja) * 2014-09-03 2016-04-14 有限会社ファインチューン アブソリュート型エンコーダ
JP2017116306A (ja) * 2015-12-22 2017-06-29 株式会社ミツトヨ エンコーダ

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